C. E. M. Pearce

Stochastic resonance (SR) - a counter-intuitive phenomenon in which the signal due to a weak periodic force in a nonlinear system can be {\it enhanced} by the addition of external noise - is reviewed. A theoretical approach based on linear response theory (LRT) is described. It is pointed out that, although the LRT theory of SR is by definition restricted to the small signal limit, it possesses substantial advantages in terms of simplicity, generality and predictive power. The application of LRT to overdamped motion in a bistable potential, the most commonly studied form of SR, is outlined. Two new forms of SR, predicted on the basis of LRT and subsequently observed in analogue electronic experiments, are described.

PURPOSE: The purpose of this article is 2-fold: To report the long-term functional results of arthroscopic rotator cuff repair (average, 3.5 years in this study), and to analyze results by tear size and repair technique (margin convergence v direct tendon-to-bone repair). TYPE OF STUDY: Case series. METHODS: Between September 1993 and April 1997, 62 patients had an arthroscopic rotator cuff repair performed by the senior author (S.S.B.). Of this group, 59 patients (59 shoulders) were available for follow-up. Preoperative and postoperative function were assessed by means of a modified UCLA scoring system. Tears were categorized according to size (greatest diameter, number of tendons involved, and pattern of tear [crescent shape v U-shape]). Crescent-shaped tears were repaired in a direct tendon-to-bone fashion and U-shaped tears were repaired by a margin-convergence technique. RESULTS: Good and excellent results were achieved in 95% of the cases, regardless of tear size. The large and massive tears did as well as the small and medium-sized tears. That is, results were independent of tear size (P >.05). Results of tears repaired by margin convergence were not significantly different statistically from those repaired by direct tendon-to-bone repair (P >.05), validating the selection criteria of U-shaped tears for repair by margin convergence. There is a rapid return to full overhead function after arthroscopic rotator cuff repair (average, 4 months for each tear size). Delay from injury to surgery, even of several years, did not adversely affect surgical outcome. CONCLUSIONS: (1) Arthroscopic rotator cuff repair can achieve good and excellent results in a large percentage of patients (95% in this series). (2) Results of arthroscopic rotator cuff repair are independent of tear size. (3) U-shaped tears repaired by margin convergence have results comparable to those of crescent-shaped tears repaired directly by a tendon-to-bone technique. (4) There is a rapid return to full overhead function after arthroscopic rotator cuff repair (average, 4 months for all tear sizes). (5) A delay from injury to diagnosis, even of several years, is not a contraindication to arthroscopic rotator cuff repair.

Stochastic resonance has been observed in many forms of systems, and has been hotly debated by scientists for over 30 years. Applications incorporating aspects of stochastic resonance may yet prove revolutionary in fields such as distributed sensor networks, nano-electronics, and biomedical prosthetics. Ideal for researchers in fields ranging from computational neuroscience through to electronic engineering, this book addresses in detail various theoretical aspects of stochastic quantization, in the context of the suprathreshold stochastic resonance effect. Initial chapters review stochastic resonance and outline some of the controversies and debates that have surrounded it. The book then discusses suprathreshold stochastic resonance, and its extension to more general models of stochastic signal quantization. Finally, it considers various constraints and tradeoffs in the performance of stochastic quantizers, before culminating with a chapter in the application of suprathreshold stochastic resonance to the design of cochlear implants.

Stochastic resonance has been observed in many forms of systems, and has been hotly debated by scientists for over 30 years. Applications incorporating aspects of stochastic resonance may yet prove revolutionary in fields such as distributed sensor networks, nano-electronics, and biomedical prosthetics. Ideal for researchers in fields ranging from computational neuroscience through to electronic engineering, this book addresses in detail various theoretical aspects of stochastic quantization, in the context of the suprathreshold stochastic resonance effect. Initial chapters review stochastic resonance and outline some of the controversies and debates that have surrounded it. The book then discusses suprathreshold stochastic resonance, and its extension to more general models of stochastic signal quantization. Finally, it considers various constraints and tradeoffs in the performance of stochastic quantizers, before culminating with a chapter in the application of suprathreshold stochastic resonance to the design of cochlear implants